外部被ばく

ICRP Publication 74:
Conversion Coefficients for use in Radiological Protection against External Radiation. (http://www.icrp.org/publication.asp?id=ICRP Publication 74)

ICRP Publication 116
Conversion Coefficients for Radiological Protection Quantities for External Radiation Exposures
(http://www.icrp.org/publication.asp?id=ICRP Publication 116)

ICRP 116 (7)
Two sets of quantities are of importance in radiological protection:
(1) protection quantities (e.g. equivalent dose and effective dose)
(2) operational quantities (e.g. ambient dose equivalent and personal dose equivalent, defined for use as measurable surrogates of the protection quantities).

ICRP 116 (8)
The three principal protection quantities remain
(1) the mean absorbed dose in an organ or tissue, DT;
(2) the equivalent dose in an organ or tissue, HT;
(3) the effective dose, E.

ICRP 116 (8)
To form a bridge between the protection quantities and the radiation field, ICRU has developed operational quantities for measurement of exposures to external radiations.

ICRP 116 (9)
The operational quantities are
(1) the ambient dose equivalent, H*(d);
(2) the directional dose equivalent, H'(d,X);
(3) the personal dose equivalent, Hp(d).

CONVERSION COEFFICIENTS FOR EXTERNAL EXPOSURE

ICRP 116 (111)
The protection quantities ‘equivalent dose’ and ‘effective dose’ are not measurable and thus their values are determined using their relationship to physical radiation field quantities such as particle fluence or air kerma.

ICRP Publication 74 (ICRP, 1996) explored the relationship between the protection quantity ‘effective dose’ and the operational dose quantities for specific idealised irradiation exposure geometries. Most of the data for protection quantities used for the evaluation were calculated on the basis of stylised models of human anatomy.

ICRP 116 (113)
The ICRP voxel-based reference phantoms representing Reference Male and Reference Female (ICRP, 2002) require new calculations of conversion coefficients for all radiations and irradiation geometries of interest to replace the existing ICRP/ICRU data sets (ICRP, 1996).